Many national and regional patent systems provide opposition mechanisms which aim at improving the quality of patents by providing third parties an opportunity to oppose the grant of a patent within a certain period of time. An opposition mechanism may be available either after the publication of a patent application or soon before the grant of a patent (pre-grant opposition) and/or after the grant of a patent (post-grant opposition) depending on the applicable law. While the design of opposition systems may differ from one country/region to another, the common objective is to provide a simple, quick and inexpensive administrative mechanism that increases quality by providing additional input to the process.
Many countries provide other, similar mechanisms, such as third party observations, re-examination and administrative revocation and invalidation. In general, they allow third parties to intervene in the patent examination process before the grant of a patent, or to challenge a patent after its grant, without having to resort to the courts. The following documents provide information on the work of the SCP regarding opposition systems and related mechanisms.